New Traces: Emma and Daniel are preparing for the murder trial of his father, and McKinven and Sarah are back together

So how do the actors involved the likes of CSI, Silent Witness and Traces cope portraying characters whose livelihood revolves around dealing with mind-boggling facts and numbers while attempting to solve gruesome crimes?

Traces returns for a second season on BBC One tonight (following its previous broadcast on Alibi) and the show’s star Molly Windsor, who plays Emma Hedges, explains how she got to grips with understanding the world of forensic science.

“It’s a completely different way of thinking,” says Molly, whose breakthrough came when she took the lead role in The Unloved in 2009, aged just 11.

“They’re so pragmatic, where as our whole career is led by imagination and kind of going off on tangents and being led by emotion.

“To learn to be dealing with facts and numbers is a whole different way of thinking. I have an even greater respect for the people who do it, so I feel even less capable.”

Windsor, who also won a Bafta for her work in acclaimed miniseries Three Girls in 2017 and starred in ITV’s 2019 thriller Cheat, explains how important forensic science is in helping her character Emma solve her mother’s murder on the hit show co-created by Val McDermid and Amelia Bullmore.

“I think she’s trying to understand it and that’s where the forensic science is so important because it deals with facts,” she says.

“When you lose someone you love, you try and make sense of it because, emotionally, it doesn’t make sense.

“They’re not there anymore and you want them there, so then you try and understand it intellectually.

“I think that’s Emma’s way of processing it. She’s never had that opportunity because she was very young when her mum died.

“So to come to forensic science and be so close to looking at the facts, I think it’s that that’s really important and really drives her.”

Tonight’s premiere begins four months after the dramatic events of the first season.

Emma is no longer a lab assistant, and is training to be a forensic chemist at the Scottish Institute for Forensic Science and Anatomy (SIFA) in Dundee.

Her mother’s murderer has been arrested and hopefully closure is just within reach – or is it?

The trail for the murder of Marie is about to begin and Emma has to appear in court, alongside her boyfriend Daniel MacAfee (Martin Compston).

While their relationship is complicated – Daniel’s dad Phil MacAfee (Vincent Regan) murdered Emma’s mum – the pair are still together. For now, at least…

As well as the trial, the team at SIFA are also investigating a bombing at a church hall.

That’s followed by more attacks, and the investigators aren’t sure if the same person has created the homemade devices and if it’s a hate crime.

However, one of their potential leads eventually has them exploring the dangerous world of incels.

Elsewhere, DI Neil McKinven (Michael Nardone) and Professor Sarah Gordon’s (Laura Fraser) seemingly innocent flirtations seemed to have turned to romance, but with both of them married, will the close colleagues act on their feelings?

We also receive a glimpse into Professor Kathy Torrence’s (Jennifer Spence) personal life, as her lack of social skills come back to bite her at work.

Real life can be baffling, even for these forensic science geniuses.